Added documentation and informations.

README.md

@@ -1,3 +1,26 @@
+![GitHub code size in bytes](https://img.shields.io/github/languages/code-size/Ayfri/discord-fetch-messages)
+![npm](https://img.shields.io/npm/dt/discord-fetch-messages)
+![npm](https://img.shields.io/npm/v/discord-fetch-messages?label=latest%20version)
+[![Language grade: JavaScript](https://img.shields.io/lgtm/grade/javascript/g/Ayfri/discord-fetch-messages.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/Ayfri/discord-fetch-messages/context:javascript)
+
 # discord-fetch
 
-A npm package to fetch all of the messages in a guild.
+A npm package to fetch all the messages from a guild or a channel.
+
+
+## How to use it
+
+<strong>⚠️ READ BEFORE USING ⚠️ <br>
+These operations took a long time to process. Be patient and avoid doing this often because it's doing a lot of requests to Discord and you can be banned for sending too many requests to Discord.
+</strong> <br>
+⚠️ READ BEFORE USING ⚠️
+<strong>
+
+```js
+const fetchedGuildMessages = await require('discord-fetch-messages').fetchGuildMessages(client, id);
+
+const fetchedChannelMessages = await require('discord-fetch-messages').fetchChannelMessages(client, id);
+```
+
+Note :
+> Node.js > 14 is required.